Class Select

Represents the Selection step of Query Evaluation.

Inheritance

System.Object

Select

Implements

IUnaryOperator

ISparqlAlgebra

IVisitable

IProcessable

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: VDS.RDF.Query.Algebra

Assembly: dotNetRdf.dll

Syntax

public class Select : IUnaryOperator, ISparqlAlgebra, IVisitable, IProcessable

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Constructors

Select(ISparqlAlgebra, bool, IEnumerable<SparqlVariable>)

Creates a new Select.

Declaration

public Select(ISparqlAlgebra pattern, bool selectAll, IEnumerable<SparqlVariable> variables)

Parameters

Type	Name	Description
ISparqlAlgebra	pattern	Inner Pattern.
System.Boolean	selectAll	Whether we are selecting all variables.
System.Collections.Generic.IEnumerable<T><SparqlVariable>	variables	Variables to Select.

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Properties

FixedVariables

Gets the enumeration of fixed variables in the algebra i.e. variables that are guaranteed to have a bound value.

Declaration

public IEnumerable<string> FixedVariables { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<T><string>

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

FloatingVariables

Gets the enumeration of floating variables in the algebra i.e. variables that are not guaranteed to have a bound value.

Declaration

public IEnumerable<string> FloatingVariables { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<T><string>

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

InnerAlgebra

Gets the Inner Algebra.

Declaration

public ISparqlAlgebra InnerAlgebra { get; }

Property Value

Type	Description
ISparqlAlgebra

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

IsSelectAll

Does this operator select all variables?.

Declaration

public bool IsSelectAll { get; }

Property Value

Type	Description
System.Boolean

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

SparqlVariables

Gets the SPARQL Variables used.

Declaration

public IEnumerable<SparqlVariable> SparqlVariables { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<T><SparqlVariable>

Remarks

If the Query supplied in the SparqlEvaluationContext is non-null then it's Variables are used rather than these.

Variables

Gets the Variables used in the Algebra.

Declaration

public IEnumerable<string> Variables { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<T><string>

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Methods

Accept<T>(ISparqlAlgebraVisitor<T>)

Declaration

public T Accept<T>(ISparqlAlgebraVisitor<T> visitor)

Parameters

Type	Name	Description
ISparqlAlgebraVisitor<T>	visitor

Returns

Type	Description
T

Type Parameters

Name	Description
T

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Accept<TResult, TContext>(ISparqlQueryAlgebraProcessor<TResult, TContext>, TContext)

Declaration

public TResult Accept<TResult, TContext>(ISparqlQueryAlgebraProcessor<TResult, TContext> processor, TContext context)

Parameters

Type	Name	Description
ISparqlQueryAlgebraProcessor<TResult, TContext>	processor
TContext	context

Returns

Type	Description
TResult

Type Parameters

Name	Description
TResult
TContext

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

ToGraphPattern()

Throws an error as a Select() cannot be converted back to a Graph Pattern.

Declaration

public GraphPattern ToGraphPattern()

Returns

Type	Description
GraphPattern

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Exceptions

Type	Condition
System.NotSupportedException	Thrown since a Select() cannot be converted back to a Graph Pattern.

ToQuery()

Converts the Algebra back to a SPARQL Query.

Declaration

public SparqlQuery ToQuery()

Returns

Type	Description
SparqlQuery

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

ToString()

Gets the String representation of the Algebra.

Declaration

public override string ToString()

Returns

Type	Description
string

Overrides

object.ToString()

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Transform(IAlgebraOptimiser)

Transforms the Inner Algebra using the given Optimiser.

Declaration

public ISparqlAlgebra Transform(IAlgebraOptimiser optimiser)

Parameters

Type	Name	Description
IAlgebraOptimiser	optimiser	Optimiser.

Returns

Type	Description
ISparqlAlgebra

Remarks

Selection trims variables from the Multiset that are not needed in the final output.

Implements

IUnaryOperator

ISparqlAlgebra

IVisitable

IProcessable

Extension Methods

Extensions.ToSafeString(object)

Extensions.AsEnumerable<T>(T)